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Glossary

Indications

Fractures of the distal metaphysis can be transverse, oblique, or
comminuted.
Always confirm the fracture configuration with views in both planes.
Irreducible and unstable fractures require ORIF.
Other indications for ORIF are open fractures, or soft-tissue lacerations.

Lag screw with protection plate

In short oblique fractures, only one lag screw can be inserted. This is
insufficient to produce enough stability. The lag screw must be protected by a
plate.
For fractures of the condylar metaphysis, a minicondylar plate is preferred,
because of the angular stability that it provides, although any conventional
plate can also be used for protection: these have the advantage of being less
bulky. This reduces the risk of compromising the gliding of the extensor
tendons.

Indirect reduction by traction

Direct reduction

Direct reduction is necessary when the fracture can not be reduced by
traction and flexion, or is unstable.
When indirect reduction is not possible, this is usually due to interposition
of parts of the extensor apparatus.
Use a pointed reduction forceps for direct reduction.

Planning lag screw position

The lag screw should be inserted as perpendicularly to the fracture line as
possible and from the dorsal surface. The direction of the obliquity of the
fracture plane dictates the exact position of the lag screw.

Drilling for lag screws

There are two options to prepare the gliding hole and the threaded hole:

1) Gliding hole firstDrill the gliding hole in the near cortex. Ensure perfect fracture
reduction and then insert a drill guide. Drill the threaded hole in the far
(trans) cortex through the drill guide.
This method ensures that the threaded hole is perfectly in line with the
gliding hole.
This is the preferred method

2) Thread hole firstDrill a hole through both cortices, using the drill for the thread hole.
Then use the corresponding larger drill bit to overdrill the near cortex to
create the gliding hole.
This technique is useful for small fragments. The disadvantage, however, is
that the holes may not be centered in relation to each other.

Pearl
If the near cortex is tapped prior to overdrilling for the gliding hole,
eccentric passage of the second drill is less likely. This can be achieved by
inserting the chosen self-tapping screw through the near (cis) cortex and then
removing it. The drill will now follow exactly the threaded axis.

Pitfall: Oblique measurement

When measuring for screw length in oblique drill holes, the measurement to
the acute angle is different from the measurement to the obtuse angle. This
problem increases with the degree of obliquity.
Always measure both angles and use the longer measurement. However, keep in
mind that too long a screw can protrude to the extent that it puts the soft
tissues at risk.

Screw length pitfalls

Too short screws do not have enough threads to engage the cortex properly.
This problem increases when self-tapping screws are used due to the geometry of
their tip.

Too long screws endanger the soft tissues, especially tendons and
neurovascular structures. With self-tapping screws, the cutting flutes are
especially dangerous, and great care has to be taken that the flutes do not
protrude beyond the cortical surface.

Pitfall: breaking the cortex in diaphyseal bone

Do not advance the countersink too deeply into the cortex: the cortical
thickness will determine the depth of countersinking. Excess penetration risks
break-through of the screw head when tightened and loss of fixation.
Countersinking is, therefore, done by hand and not with a power tool.

Insert lag screw

Planning plate position

It is wise to use magnifying loupes for this step.
Plan the blade position as dorsal as possible, in order not to injure the
collateral ligament.
Make sure that the plate will be perfectly aligned with the long axis of the
proximal phalanx in the lateral view.

Corresponding flare

The minicondylar blade plates are available in two forms. One fits on the
ulnar aspect of the bone, and the other on the radial aspect. It is a common
mistake to choose the wrong one. The correct implant will have the blade dorsal
and the distal screw hole palmar.

Trim the plate

Adapt the plate length to fit the length of the proximal phalanx. Avoid
sharp edges which may be injurious to the tendons. There should be at least 3
plate holes distal to the fracture available for fixation in the diaphysis. At
least two screws need to be inserted into the diaphysis.

Prepare the bladeMeasure the length of the drill hole.
Cut the blade to the determined length, so that it just fills the drill
hole.

Pearl: Cut the blade transversely

If you cut the blade on the flat, it will compress and widen very slightly
as it is cut. This makes its maximal width very slightly larger than 1.5 mm. It
may not fit in the 1.5 mm hole that you have drilled.
Therefore, cut the blade on edge (to deform it through its narrower dimension)
to the correct length. The resultant tip is somewhat arrow-shaped.

Pitfall: avoid dangerous edge

If you are using a dedicated minicondylar plate cutter which trims the plate
by a shearing action, be very careful not to create a sharp dorsal edge that
will endanger the extensor apparatus. Correct cutting will produce the sharp
edge on the bone side of the plate.

Pitfall: Protrusion of the blade

Avoid protrusion of the blade through the opposite cortex, as friction
during movement and eventual ligament injury may result.
Due to the fact that the phalanx is wider on the palmar side that on the dorsal
side, an AP or PA x-ray view may suggest that the blade is fully contained
within the bone, whereas in transverse section, it actually protrudes.